The present invention relates to a device for securely holding a workpiece or a part. More particularly, the present invention relates to a device having a clamping action provided by a sliding member which engages and urges the workpiece against a stop.
Many mechanical operations require that one or more workpieces be held stationary for a period of time. Various types of clamps and other devices are known in the art for securing a workpiece in a desired position to facilitate an operation on the workpiece.
An apparatus for securing one or more workpieces is shown in Bishop U.S. Pat. No. 4,805,888, issued Feb. 21, 1989. The Bishop patent describes an orbital action clamp comprised of a bolt-like member, a sliding clamp member and a mounting platen. The bolt-like member is formed of a threaded shaft and an eccentric head. The sliding clamp member has a centered through bore adapted to receive the shaft of the bolt-like member. A larger bore, concentric with the through bore, accepts the head and provides a shoulder such that the head will nest within the larger bore. The threaded section of the bolt-like member engages a threaded bore in the mounting platen.
Rotation of the Bishop bolt-like member results in an orbital action by the head. That is, rotation of the eccentric head within the clamp member produces a camming action against a wall of the large bore of the clamp member. This camming action produces motion of the clamp member in two directions. The first motion is against the stop, while the second is across the clamping surface.
In most cases, the Bishop clamp member will be fully engaged with the workpiece without being securely anchored to the platen. In some cases, the head will tighten against the shoulder of the clamp member before the workpiece is clamped to the stop.